Olefin metathesis has been used extensively to produce smaller molecules from unsaturated molecules or polymers. Ethenolysis, cross-metathesis with ethylene, has become particularly important, as it has proved useful in making terminal olefins. These processes, however, produce a statistical distribution of products based on the thermodynamic equilibrium of the reaction.
With the development of more effective metathesis catalysts, particularly those with the N-heterocyclic carbene ligand, the use of acrylates and other electron deficient olefins for ethenolysis has become possible. It was observed, however, that the cross-metathesis reaction between an electron-deficient olefin, such as an acrylate, and a relatively electron-rich olefin is essentially irreversible under metathesis conditions. This property of acrylates was utilized to synthesize an alternating copolymer by inserting a diacrylate into a ROMP polymer, see Choi et al., Angew. Chem. 2002, 114, 3995-7. In similar fashion, alternating copolymers have been prepared by ADMET by the use of a diacrylate, see Demel et al., Macromol. Rapid Commun. 2003, 24, 636-41 and Schulz et al., Macro Lett. 2012, 1, 449-51.
There remains a need for the metathesis depolymerization of olefin containing polymers or cross-metathesis with other polyenes to yield useful products. Furthermore, a depolymerization process that: permits formation of useful products; can be carried out with or without employing a solvent; can be carried out over a wide range of pressures or temperatures; does not result in undesired side product; permits incorporation of a variety of desired functionality into a final depolymerization product; and/or permits further modification to a useful product remains a goal.